Hexon isolated from simian adenovirus serotype 19, hypervariable region thereof and chimeric adenovirus using the same

ABSTRACT

Novel hexon isolated from simian adenovirus serotype 19 encoded in the polynucleotide defined as SEQ ID NO: 3, hepervariable region thereof, chimeric adenovirus comprising the same, and therapeutic use thereof provides a solution to the problem of safety and effective systemic treatment for developing gene therapeutic agents using adenovirus.

FIELD OF THE INVENTION

The present invention relates to novel hexon isolated from simian adenovirus serotype 19 (“SAd19”), hypervariable region (“HVR”) thereof, chimeric adenovirus using the same, and a therapeutic use thereof.

BACKGROUND OF THE INVENTION

Adenovirus belongs to the family Adenoviridae first isolated in 1953. Human adenoviruses are categorized into six (6) subgenera (A through F) based on the genome similarity, oncogenecity, and blood coagulation characteristics. Adenoviruses infect most non-divided cells such as muscle, lung, brain, and cardiac cells, and its molecular biological characteristics are well known in the art. Its genome is composed of a linear, double-stranded DNA of 35 kb and its replication in the host cell depends on viral protein, E1A.

Above characteristics of adenovirus can be exploited by using a nonreplicative vector having E1A deleted therefrom. Since the development of HEK293 cell line in which the adenoviral E1 gene is inserted, the adenovirus vector system has been used in numerous studies, which has led to the development of virotherapeutics that utilize cytotoxicity of the host cell. Oncorine®, which is the oncolytic virotherapeutics commercialized in China in 2005, is an E1B55-defective adenovirus for selectively inducing apoptotic cell death in p53-defective tumor.

In the development of selective replicative adenovirus therapeutic agents, selective expression of E1A protein is most important, and there have been suggested many cases regarding possible tumor-selective adenovirus gene therapeutic agents using tumor selective expression promoter. Most of the tumor-selective adenoviruses are prepared using the commonly-found human adenovirus serotype 5 (“HAd5”). It has been reported that human has high levels of adenovirus neutralizing antibodies, since HAd5 occupies 80% of prevalence (Appaiahgari, M. B., et al. (2007) Clinical and Vaccine Immunol. 14, 1053-1055). These neutralizing antibodies against adenoviral capsid protein influence the efficacy and toxicity of the adenovirus systemically administered (Chen, Y., et al. (2000) Hum. Gene Ther. 11, 1553-1567).

Viral capsid consists of three (3) kinds of proteins, i.e., hexon, fiber, and penton, and comprises a capsomere having a symmetric icosahedron structure consisting of 240 hexons and 12 pentons. Each penton binds a protruded trimeric fiber of 70˜100 nm. When infected by adenovirus, the trimeric fiber attaches to Coxackie Adenovirus Receptor (CAR) on the surface membrane of host cell in the process of adenovirus infection. The RGD region of penton binds to integrin, which leads to viral absorption and penetration into the host cell.

It has been reported that Loop 1 (L1) and Loop 2 (L2) of a hexon protein are exposed on the outside of the viral capsomere structure. L1 and L2 respectively contain six (6) hypervariable regions (HVRs), i.e., HVR-1 to HVR-6 within the 132^(nd) to 320^(th) amino acids and seventh HVR (HVR-7) within the 408^(th) to 459^(th) amino acids of the hexon protein.

The adenoviruses provide an elegant and efficient means of transferring therapeutic genes into cells. However, one problem encountered with the use of adenoviral vectors for gene transfer in vivo is the generation of antibodies to antigenic epitopes on adenoviral capsid proteins.

When adenovirus is administered to human body, neutralizing antibodies against hexon proteins are formed, and such antibodies mostly target the dominant HVR regions. It is also known that the antibodies reduce the efficiency of viral replication by way of inhibiting the infection of host cells (Wohlfart, C. (1988) J. Virol. 62, 2321-2328, Toogood, C. I. A., et al. (1992) J. Gen. Virol. 73, 1429-1435. Sumida, S. M., et al. (2005) J. Immunol. 174, 7179-7185).

The problems caused by the preponderance of human neutralizing antibodies against HAd5 in human must be overcome when administering adenovirus using a viral gene delivery vector and viral therapeutic agent. In addition to the above mentioned problems associated with the neutralizing antibodies, it has been reported that adenoviruses infect the liver when exposing systemically. In this connection, adenovirus has been reported to have hepatotropism, and when adenoviruses are administered via an intravenous route, 90% thereof is transferred to the liver within 24 hours (Worgall, S., et al. (1997) Hum. Gene Ther. 8, 37-44). Due to such hepatoselectivity of the adenovirus, in 1999, young patient, Jessie Gelsinger, under a clinical trial using gene therapeutic adenovirus agents succumbed due to acute hepatotoxicity. Thus, dose of adenovirus has been restricted to an amount that does not exceed 1×10¹³ vp since then. Therefore, hepatotoxicity is generally considered as a dose-limiting factor in nonclinical/clinical trials for many gene therapeutic agents using adenovirus (Alemany, R. et al. (2001) Gene Ther., 8(17), 1347-1353; Christ, M., et al. (2000) Hum. Gene Ther., 11(3), 415-427; Lieber, A., et al. (1997) J. Virol., 7(11), 8798-8807). Such liver selectivity is a major problem in achieving efficient cure by systemic administration of an adenoviral therapeutic agent (Worgall, S., et al. (1997) Hum. Gene Ther., 8, 37-44).

In this regard, Waddington et al. have recently reported that Gla domain, blood coagulating factor, combines with hexon protein of adenovirus in blood, which facilitates adenovirus transfer to the liver (Waddington, S. N., et al. (2008) Cell, 132, 397-409). It has been speculated that HVR-3, HVR-5 or HVR-7 of hexon can combine with blood coagulating factor, Gla domain (Kalyuzhniy, O., et al. (2008) Proc. Nat'l Acd. Sci. 105, 5483-5488). The HVR varies depending on the serotype of adenovirus, and it is not clear yet what is the crucial factor for binding affinity to blood coagulating factor. It has been reported that the maximum tolerated dose of adenovirus can be raised tenfold by way of inserting a specific protein such as RGD, RFP, and BAP (Biotin Acceptor Peptide) to significantly weaken binding affinity to blood coagulating factor and to reduce the hepatotropism (Shashkova, E. V., et al. (2009) Mol. Ther. 17, 2121-2130).

A number of functions of the hexon protein are now known, and many studies to modify hexon proteins in order to overcome the problems of hepatotoxicity and anti-adenoviral immunity are currently being conducted. There are four strategies for modifying hexon protein: 1) replacing the hexon gene with the corresponding hexon gene of other adenovirus serotype, 2) inserting a peptide into HVR, 3) replacing the gene encoding HVR of a hexon protein with the corresponding gene encoding HVR of other adenovirus serotype, and 4) removing the region from the HVR that binds the blood coagulating factor and neutralizing antibody. Up to date, the method of inserting a peptide into the HVR and the method of replacing the gene encoding HVR with the corresponding gene encoding HVR of other adenovirus serotype are carried out for hexon modification. Among above mentioned four strategies, complete hexon substitution is most apparent method to change viral immunogenicity. However, a method to achieve complete hexon exchange for modifying hexon protein has the problem of deteriorated productivity due to the fact that subtle structural differences in binding hexon to penton and fiber induce instability of the adenoviral capsid structure (Roberts, D. M., et al. (2006) Nature, 441, p 239-243; Youil, R., et al. (2002) Hum. Gene. Ther. 13, p 311-320; Shashkova, E., et al. (2009) Mol. Ther. 17, 2121-2130).

Further, intense studies for the modification of capsid protein using serotypes of heterogenous adenovirus as well as those of human adenovirus are in progress. It has been reported that the prevalence rate of neutralizing antibodies against chimpanzee adenoviruses pan 5, 6, 7 and 9, classified as simian adenovirus serotypes 22 to 25, respectively, is less than 6%, and therefore, a simian adenoviral vector system including chimpanzee adenovirus can be useful as a gene therapeutic vector (Roy, S. et al. (2004) Hum. Gene Ther. 15, p 519-530). International Patent Publication Nos. WO 2006/040330 and WO 2002/083902 teach the use of the fiber or hexon protein of human serotypes 11, 24, 26, 30, 34, 35, 48, 49, and 50 for suppressing immune response caused by neutralizing antibodies in the recombinant chimeric adenovirus where the adenoviral knob domain binding to the CAR or a hexon protein is substituted with those of other serotypes. Regarding simian adenovirus serotype, International Publication No. WO 2005/001103 discloses a chimeric adenovirus using simian adenovirus serotype 18.

However, there exists a strong need to develop an adenovirus having lower immunogenicity and lower toxicity. Thus, the present inventors have identified a novel SAd19 hexon gene isolated from baboon excrements and have found that it is highly capable of evading the neutralizing antibodies against HAd5 and it exhibits a low toxicity.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide a novel hexon protein and a DNA encoding the same for use in the preparation of a chimeric adenovirus.

It is another object of the present invention to provide a chimeric adenovirus comprising the novel hexon protein.

It is a further object of the present invention to provide a composition comprising the chimeric adenovirus.

It is a still further object of the present invention to provide a method of gene therapy employing the chimeric adenovirus.

In accordance with one aspect of the present invention, there is provided a hexon isolated from SAd19 and a DNA encoding the hexon.

In accordance with another aspect of the present invention, there is provided a HVR of the hexon isolated from SAd19 and a DNA encoding the HVR.

In accordance with a further aspect of the present invention, there is provided a chimeric adenovirus having a normative amino acid sequence in the hexon by the substitution of the hexon protein isolated from SAd19, or seven (7) or more consecutive residues therefrom.

In accordance with a still further aspect of the present invention, there is provided a composition comprising the chimeric adenovirus of the present invention.

In accordance with a still further aspect of the present invention, there is provided a method for delivering a therapeutic transgene to a mammalian cell comprising introducing into said cell the chimeric adenovirus of the present invention.

In accordance with a still further aspect of the present invention, there is provided a method for treating cancers comprising administering into a subject the chimeric adenovirus of the present invention.

In accordance with a still further aspect of the present invention, there is provided a method for preparing an adenoviral vector for gene therapy comprising substituting seven (7) or more amino acid residues in the hexon of a human adenovirus with seven (7) or more residues of the hexon protein of the present invention.

In accordance with a still further aspect of the present invention, there is provided an isolated host cell comprising the chimeric adenovirus of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects and features of the present invention will become apparent from the following description of the invention, when taken in conjunction with the accompanying drawings, which respectively show:

FIG. 1: amino acid sequences of hexon proteins from human adenovirus (HAd) serotypes 5 (A) and 41 (B), and SAd19;

FIG. 2: cleavage maps of pHex-SAd19 Hexon vector (A), pAd H5/S19_(—)8DS vector (B), pAd328 H5/S19_DS vector (C), and pAd328 H5/S19_DS Δ19k (D);

FIG. 3: the results of western blot analysis showing the expression level of tumor-specific EIA proportional to infected units of Ad H5_(—)8DS and Ad H5/S19_(—)8DS;

FIG. 4: SPR results for measuring the binding affinity between human blood coagulating factor X and Ad H5/S19_(—)8DS (A) and the western blot result for human blood coagulating factor and adenoviral fiber protein after co-immunoprecipitation of human blood coagulating factor IX or X with either Ad H5_(—)8DS, Ad H5/S19_(—)8DS, Ad328 H5/S19_DS or Ad328 H5/S19_DS Δ19k (B-D);

FIG. 5: results of agarose gel electrophoresis showing the PCR-amplified DNA bands of adenoviral fiber gene in respective organs after intravenous injection of Ad H5_(—)8DS and Ad H5/S19_(—)8DS;

FIG. 6: Western blot analysis results demonstrating the infection-evading ability of chimeric adenoviruses having hexon of simian adenovirus serotype 19, Ad H5/S19_(—)8DS (A), Ad328 H5/S19_DS and Ad328 H5/S19_DS Δ19k (B), by employing neutralizing antibodies against HAd5;

FIG. 7: an immunostaining photograph and bar graph showing the infection-evading ability of chimeric adenoviruses having hexon of SAd19, Ad H5/S19_(—)8DS (A), Ad328 H5/S19_DS and Ad328 H5/S19_DSΔ19k (B), by employing neutralizing antibodies against HAd5;

FIG. 8: a graph showing the expression pattern of LK8 gene in blood transferred by Ad H5/S19_(—)8DS and Ad H5_(—)8DS which are administered to Syrian hamster immunized by HAd5;

FIG. 9: a photograph of each organ excised from autopsied mice into which Ad H5_(—)8DS and Ad H5/S19_(—)8DS are intravenously administered dose-dependently;

FIG. 10: blood analysis data of the mice into which Ad H5_(—)8DS is intravenously administered;

FIG. 11: blood analysis data of the mice into which Ad H5/S19_(—)8DS is intravenously administered;

FIG. 12: a tumor-growth curve in the animal model for H460 non-small cell lung cancer after intravenous injection of Ad H5/S19_(—)8DS;

FIG. 13: a lung photograph of the animal model for H2172 orthotopic lung cancer autopsied after injection of tumor-specific chimeric adenovirus, Ad H5/S19_(—)8DS depending on the immunization against HAd5; and

FIG. 14: the results of analysing the volume, weight, the number and the size of the tumors on the lungs of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention belongs. Further, all documents mentioned herein are incorporated by reference in their entireties.

The term “adenovirus” as used herein refers to a non-enveloped icosahedral double-stranded DNA virus having about a linear genome of about 36 kb.

The term “chimeric adenovirus” as used herein refers to an adenovirus whose nucleic acid sequence is comprised of the nucleic acid sequences of at least two of the adenoviral serotypes.

As used herein, “substitution” results from the replacement of one or more polynucleotides or amino acids by different polynulceotides or amino acids, respectively.

The term “hypervariable region” or “HVR” as used herein means a variable domain, whose sequence is hypervariable, forming structurally limited loop.

The term “normative amino acid sequence” as used herein means any amino acid sequence that is not found in the native hexon protein of a given serotype of adenovirus, and is introduced into the hexon protein at the level of gene expression (i.e., by production of a nucleic acid sequence that encodes the normative amino acid sequence).

The term “therapeutic transgene” as used herein refers to a polynucleotide that is introduced into a cell and is capable of being translated and/or expressed under appropriate conditions and confers a desired property to a cell into which it was introduced, or otherwise leads to a desired therapeutic outcome.

The term “vector” as used herein refers to a vehicle for gene transfer as that term is understood by those skilled in the art, and includes viruses, plasmids, and the like.

The term “neutralizing antibody” as used herein means an antibody being able to inhibit infectivity of (i.e., cell entry) or gene expression commanded by an adenovirus. The neutralizing antibody may be an antibody that either is purified from or is present in serum.

The present invention is described in detail hereinafter.

In the present invention, there is provided a hexon isolated from SAd19, a HVR thereof and DNAs encoding the hexon.

The SAd19 according to the present invention may be provided by the isolation from the baboon excrements and is classified as subgroup F. The hexon of SAd19 has an amino acid sequence of SEQ ID NO: 16, which has 85% homology with that of the human adenovirus serotype 41 (“HAd41”) hexon and 76% homology with that of HAd5 hexon. Further, the nucleotide sequence encoding the hexon of SAd19 has 76% homology with that of the HAd41 hexon and 70% homology with that of the HAd5 hexon. Preferably, the hexon of SAd19 according to the present invention has the DNA sequence of SEQ ID NO: 3.

The hexon of SAd19 or seven (7) or more residues therefrom may be incorporated into various types of adenoviruses by the substitution in order to provide a chimeric adenovirus. Accordingly, there is provided a chimeric adenovirus having a normative amino acid sequence in the hexon by the substitution of the hexon protein of SAd19 of the present invention, or one or more residues therefrom.

Preferably, the chimeric adenovirus may have a normative amino acid sequence in the hexon by the substitution of seven (7) or more residues from the hexon having the amino acid sequence of SEQ ID NO: 16. The seven (7) or more residues from the hexon of SAd19 may be HVR. The HVR may have the amino acid sequence of SEQ ID NO: 21 and may be encoded by the nucleotide sequence of SEQ ID NO: 20. More preferably, the chimeric adenovirus may have a normative amino acid sequence in the hexon by the substitution of the fragment of the HVR, i.e., HVR-1 to -7, which correspond to the amino acid residues 11 to 41, 46 to 52, 69 to 78, 106 to 119, 126 to 138, 160 to 173, and 275 to 303 of SEQ ID NO: 21, respectively.

The chimeric adenovirus having the hexon of SAd19 or seven (7) or more residues therefrom shows little immune inhibition by neutralizing antibodies and hepatotoxicity.

Various types of the adenovirus, preferably human adenovirus serotype, more preferably, human adenovirus serotypes 5, 11, 24, 26, 30, 34, 35, 48, 49, and 50 may be useful for the preparation of the present chimeric adenovirus. Tumor-specific, replication-competent adenovirus or tumor-specific, replication-restricted adenovirus may be useful as the adenovirus therapeutic agent. The chimeric adenovirus of the present invention has a normative amino acid sequence so as to overcome problems of immune response and hepatotoxicity.

In particular, the normative amino acid sequence according to the present invention is prepared by substituting a hexon region of a wild-type adenovirus with that of SAd19. Optimally the resultant normative amino acid sequence is such that seven (7) or more of the existing epitopes for neutralizing antibodies directed against the corresponding wild-type adenovirus hexon protein have been rendered non-immunogenic.

According to the present invention, the chimeric adenovirus comprises hexon modification of seven (7) or more amino acids, and such hexon modification is made in seven (7) or more regions.

The most preferable chimeric adenovirus may be Ad H5/S19_(—)8DS, which is prepared by transduction of the adenoviral vector pAd H5/S19_(—)8DS into human lung adenocarcinoma epithelial cell line, A549, thereby substituting human adenoviral hexon with the hexon of SAd19.

In a preferred embodiment of the present invention, the chimeric adenovirus of the present invention may further contain therapeutic transgene. The non-limiting examples of such therapeutic transgene include tumor suppressor gene, antigenic gene, cytotoxic gene, cytostatic gene, suicide gene, anti-angiogenic gene and immune-modulatory gene.

Concretely, the “tumor suppressor gene” is a nucleotide sequence, the expression of which in the target cell is capable of suppressing the neoplastic phenotype and/or inducing apoptosis. Examples of the tumor suppressor gene include p53-gene, APC-gene, DPC-4/Smad4 gene, BRCA-1 gene, BRCA-2 gene, WT-1 gene, retinoblastoma gene (Lee et al., Nature, 1987, 329,642), MMAC-1 gene, adenomatous polyposis coil protein (U.S. Pat. No. 5,783,666), DCC (deleted in colorectal cancer) gene, MMSC-2 gene, nasopharyngeal cancer suppressor gene located on chromosome 3p21.3 (Cheng et al., Proc. Nat. Acad. Sci., 1998, 95, 3042-3047), MTS1 gene, CDK4 gene, NF-1 gene, NF-2 gene, VHL gene, etc.

The “antigenic gene” is a nucleotide sequence, the expression of which in the target cells results in the production of a cell surface antigenic protein capable of recognition by the immune system. In the example of this antigenic gene, the carcinoembryonic antigen (CEA), CD3, CD133, CD44, and p53 (International Publication No. WO94/02167) are included. For easy recognization of the immune system, the antigenic gene may be combined with the MHC type I antigen.

The “cytotoxic gene” is a nucleotide sequence exhibiting the toxic effect when expressed in cells. Examples of the cytotoxic gene include nucleotide sequences coding Pseudomonas exotoxin, ricin toxin, diphtheria toxin, etc.

The “cytostatic gene” is a nucleotide sequence inducing cell cycle arrest when expressed in cells. The non-limiting examples of the cytostatic gene include p21, retinoblastoma gene, E2F-Rb fusion protein gene, genes coding cyclin-dependent kinase inhibitor (for example, p16, p15, p18, and p19), growth arrest specific homeobox (GAX) gene (International Patent Publication Nos. WO97/16459 and WO 96/30385), etc.

The “suicide gene” is a nucleotide sequence inducing cell death through apoptosis when expressed in the cell. The non-limiting examples of the suicide gene encompasses genes coding herpes simplex virus thymidine kinase, varicella thymidine kinase, cytosine deaminase, purine nucleoside phosphorylase, beta-lactanase, carboxypeptidase G2, cytochrome P450-2B1, nitroreductase, beta-glucuronidase, TRAIL (TNF related apoptosis-inducing ligand), etc.

The “anti-angiogenic gene” is a nucleotide sequence, the expression of which results in the extracellular secretion of anti-angiogenic factors. The anti-angiogenic factor encompasses angiostatin, inhibitor of vascular endothelial growth factor (VEGF) and placental growth factor (P1GF) such as soluble VEGFR1 (sFLT-1) (PNAS (USA), 1998, 95, 8795-800), endostatin, and apolipoprotein (a) kringle domain (LK8). The preferred anti-angiogenic gene is a gene encoding LK8. LK8 directly influence the vascular endothelial cell to induce apoptosis and inhibit the migration of the epithelial cell (Kim J S et al., J. Biol. Chem., (2003) 278:29000). In particular, it has been reported that adenovirus-mediated expression of LK8 suppresses hepatocellular carcinoma growth in mice (Lee K. et al., Hepatology (2006) 43:1063). Therefore, it is expected that oncolytic effect of adenovirus may be improved by the introduction of LK8.

The “immune-modulatory gene” is a nucleotide sequence, which modulates humoral and cellular immune response, when expressed in the cell. The non-limiting examples of the immuno-modulatory gene encompass genes coding CD16, CTLA-4, IL24, GM-CSF, etc.

The therapeutic transgene may be inserted into the inventive chimeric adenovirus by various DNA recombinant technologies known in the art.

The present invention also provides the use of the inventive chimeric adenoviruses for the inhibition of tumor cell growth, as well as for the preparation of adenoviral vectors to deliver therapeutic transgene useful in the treatment of tumor and other disease. Specifically, there are provided a method for delivering a therapeutic transgene to mammalian cell comprising introducing said cell the chimeric adenovirus of the present invention; a method for treating cancers comprising administering said adenovirus into a subject; and a method for preparing an adenoviral vector for gene therapy comprising substituting seven (7) or more amino acid residues in the hexon of a human adenovirus with seven (7) or more residues of the SAd19 hexon protein.

In the present invention, there is also provided a composition comprising the chimeric adenovirus of the present invention. The composition of the present invention is useful for gene therapy or viral therapy, preferably for cancer treatment.

The compositions of the present invention may be formulated so as to provide various formulations together with pharmaceutically acceptable carrier and/or excipient. Thus, the formulations may be in the form of a solution in oil or water medium, suspension or emulsion, extract, powder, granule, tablet or capsule.

For oral formulation, various preparation methods including those specifically designed for adenovirus release may be used, for example, by employing Eudragit or timeclock release system (Lubeck et al., Proc. Natl. Acad. Sci. USA, 86(17), 6763-6767 (1989); and Chourasia and Jain, J. Pharm. Pharm. Sci., 6(1), 33-66 (2003)).

As mentioned above, the chimeric adenovirus may be transferred via any gene transfer systems known in the art. A lot of gene transfer system such as those disclosed in [Rolland (1998) Crit. Rev. Therap. Drug Carrier Systems 15: 143-198] and the references cited therein are well known in the art. Accordingly, the composition of the present invention may be formulated suitable for these gene transfer system.

The composition of the present invention may comprise any pharmaceutically acceptable carriers known in the art. Examples of suitable carriers are water, salt water, alcohol, lipid, wax, buffer solution, solid carrier such as mannitol, lactose, starches, magnesium stearate, sodium saccharin, talc, cellulose, glucose, sucrose, and magnesium carbonate, or biodegradable microsphere (e.g., polylactate polyglycolate).

The composition of the present invention may be provided in the form of single dose or multi-dose container such as sealed ampule or vial. Preferably, such container may be sealed so as to conserve aseptic condition of pharmaceutical formulations before using. In general, the formulation may be preserved as suspension, fluid, and emlusion in oil or aqueous vehicle. Further, the pharmaceutical formulation may be preserved under freeze drying conditions.

The chimeric adenovirus and the compositions comprising the same may be administered with site-specific injection or intravenous injection. Site-specific injection includes, for example, intraperitoneal injection, intrapleural injection, intrathecal injection, intraarterial injection, intratumoral injection or local application. Such administering methods may be also readily applied to the combination of the treatment utilizing adenoviral vector and the treatment for other target diseases. The preferred method is intravenous injection.

It should be understood that the suitable amount of the active ingredient actually administered ought to be determined in light of various relevant factors including the condition to be treated, the age and weight of the individual patient, food, administration time, excretion rate, the severity of the patient's symptom and reaction susceptibility; and, therefore, the above dose should not be intended to limit the scope of the invention in any way. Generally, the composition of the present invention contains 1×10⁷ to 1×10¹³ pfu/ml of the present chimeric adenovirus, and the present chimeric adenovirus may be injected in amount of 1×10¹¹ pfu once a week for 3 to 5 weeks.

The composition of the present invention may be used as the single therapy. But it may be combined with other anti-tumor protocols, such as conventional chemotherapy or radiation therapy for treating cancer. The chemotherapy drug which can be used with composition of the present invention encompasses paclitaxel, cisplatin, carboplatin, procarbazine, mechlorethamine, cyclophosphamide, ifosfamide, melphalan, chlorambucil, bisulfan, nitrosourea, dactinomycin, daunorubicin, doxorubicin, bleomycin, plicomycin, mitomycin, etoposide, tamoxifen, taxol, transplatinum, 5-fluorouracil, vincristin, vinblastin and methotrexate. The radiation therapy which can be used with the composition of the present invention may be X-ray irradiation and y-ray irradiation, etc.

The chimeric adenovirus of the present invention hardly renders liver transduction since it does not interact with blood coagulation factors, and exhibits low hepatotoxicity. Accordingly, the high dose of the present chimeric adenovirus may be administered to a subject due to its low risk of immune response and hepatotoxicity and, therefore, the present chimeric adenovirus is useful for safe and efficient gene therapy and viral therapy.

The following examples are intended to illustrate the present invention without limiting its scope.

Example 1 Identification of Hexon Gene of SAd19

A hexon gene was amplified from SAd19 using PCR, cloned into a pGEM-T easy vector, and sequenced with an ABI automatic DNA sequencer.

<1-1> Identification of Hexon Gene

The genome of SAd19 was isolated using a DNeasy Tissue Kit (QIAGEN, Germany) and used as a template for the amplification of a hexon gene via PCR with a primer set of SEQ ID NOs: 1 and 2. The amplified hexon gene was purified by Wizard® SV Gel and PCR Clean-Up system (Promega, WI, USA) and inserted into a pGEM-T easy vector (Promega, WI, USA) with the aid of T4 DNA ligase (Roche, Switzerland). The resulting recombinant vector was named pGEM-SAd19 Hexon vector. After transformation of E. coli cells with the vector, the vector DNAs were extracted from 10 clones of the transformants and sequenced by employing an ABI automatic DNA sequencer. Among the 10 base sequences was selected the one which had the highest sequence homology with others, thereby determining the nucleotide sequence of the hexon gene of SAd19 (SEQ ID NO: 3).

<1-2> Comparison with Base and Amino Acid Sequences of Human Adenovirus Serotypes

The base and amino acid sequences of the hexon gene of SAd19 were compared with those of 51 human serotype adenoviruses. The hexon of SAd19, belonging to subgroup F, was found to be most similar to that of HAd41, with 85% homology in amino acid sequence therebetween. It showed an amino acid homology of 76% with the hexon of HAd5. Further, the hexon of SAd19 was found to share nucleotide sequence homologies of 76% and 70% with those of HAd41 and HAd5, respectively (FIG. 1).

Example 2 Preparation of Chimeric Adenovirus with Hexon of SAd19 Substituted Therein

A shuttle vector for exchanging a hexon gene was constructed and named pHex vector, which is carrying left- and right-extended regions of hexon gene for homologous recombination. The hexon gene of SAd19 was cloned into unique restriction site of pHex vector, locating between left- and right-extended arms of hexon to afford a recombinant vector, named pHex-SAd19 Hexon. SphI-linearized pHex-SAd19 Hexon was subject to homologous recombination with AsiSI-linearized pAd H5_(—)8DS in BJ5183 (Stratagene, CA, USA) to give a SAd19 Hexon-carrying recombinant vector, named pAd H5/S19_(—)8DS. After being linearized with Pad, the pAd H5/S19_(—)8DS was transfected into A549 cells to generate novel chimeric adenovirus with the hexon of SAd19 anchored therein (Ad H5/S19_(—)8DS).

<2-1> Construction of Shuttle Vector

A shuttle vector suitable for the substitution of a hexon gene through homologous recombination was constructed. In this regard, an about 1 kb-long region upstream of the 5′ end of the hexon gene of HAd5 was amplified by PCR using a set of the primers of SEQ ID NOs: 4 and 5. The PCR product thus obtained was named Hexon L, and then inserted into pCR2.1 Topo vector (Invitrogen, CA, USA). A DNA sequence analysis allowed the selection of a clone free of mutation, which was named pCR2.1-Hexon L. Separately, an about 1 kb-long region downstream of the 3′ end of the hexon gene of HAd5 was amplified by PCR using a set of the primers of SEQ ID NOs: 6 and 7. The PCR product thus obtained was named Hexon R, and then inserted into pCR2.1 Topo vector (Invitrogen, CA, USA). A mutation-free clone, as analyzed by DNA sequencing, was named pCR2.1-Hexon R.

After being excised from pCR2.1-Hexon L by use of both XhoI and EcoRI, Hexon L was inserted into pENTR2B (Invitrogen, CA, USA), which was previously cut with both SalI and EcoRI, to give a recombinant vector, pENTR2B-Hexon L. pCR2.1-Hexon R was digested with HindIII, followed by treatment with a Klenow fragment to make blunt ends. Digestion with EcoRI excised Hexon R from the blunt-ended pCR2.1-Hexon R. This Hexon R was inserted into an Blunted XbaI and EcoRI site of the pENTR2B-Hexon L vector. The resulting recombinant vector was named pHex. PCR was performed in the presence of pfu polymerase (Stratagene, CA, USA) using a set of the primers of SEQ ID NOs: 1 and 2, with pGEM-SAd19 Hexon serving as a template. The Mfe-1-resticted hexon gene of SAd19 was cloned into EcoRI site of pHex vector. The resulting recombinant plasmid, which was found to have the hexon of SAd19 in a correct position as analyzed by DNA sequencing, was named pHex-SAd19 Hexon (FIG. 2A).

<2-2> Substitution with the Hexon of SAd19 through Homologous Recombination

In order to prepare a chimeric adenovirus recombined with the hexon of SAd19, first, pENTR2B vector (Invitrogen, CA) was treated with EcoRI to remove ccdB region therefrom. The pAAV-CMV_LK8_UN vector, previously constructed by the present inventors (see PCT Publication No. WO2009/102085), was treated with KpnI/BglII to give a CMV_LK8 fragment (later blunt ended) which was then inserted into a KpnI/XhoI site (later blunt ended) of the EcoRI-treated pENTR2B to give a recombinant plasmid pENTR-CMV_LK8.

In order to construct plasmid vector carrying tumor specific expression unit of E1A gene, the proximal promoter region of DNMT-1 (DNA (cytosine-5)-methyltransferase) gene (DS promoter) was amplified from human genomic DNA and cloned into pCR2.1-TOPO vector (Invitrogen, CA) to give a recombinant plasmid pCR-DS. Gene amplification was conducted in the presence of Ex-Taq polymerase (Takara, Japan) by PCR using human genomic DNA as PCR template and a set of the primers of SEQ ID NO: 8 (5′-CTT CTC GCT GCT TTA TCC CCA TC-3′) and SEQ ID NO: 9 (5′-CTC GGA GGC TTC AGC AGA CGC-3′), which binds to both ends of proximal promoter region of DNMT-1 gene. Starting from denaturation at 94° C. for 5 min, PCR was performed with 30 cycles of denaturing at 94° C. for 30 sec, annealing at 56° C. for 30 sec and extension at 72° C. for 1 min, followed by extension at 72° C. for additional 3 min.

A DNA fragment excised from pCR-DS by SacI and XhoI was inserted ClaI and SalI sites in front of mutant E1A gene in the pΔE1Sp1B-E2F-1 Rb7Δ19k vector (Kim, J., et al. (2007) Hum. Gene Ther. 18, p 773-786; mE1A, Korean Patent No. 746122; ΔE1B19K, Korean Patent No. 432953) to construct a recombinant plasmid pSP72-DS_mE1A_ΔE1B19K. A fragment resulting from the treatment of pSP72-DS_mE1A_ΔE1B19K with BamHI was inserted into a BglII site of pENTR-CMV_LK8 to afford a shuttle vector, named pENTR-CMV_LK8-DS_mE1A_ΔE1B19K.

To a mixture of 100 ng of pAd-PL Dest (Invitrogen, CA, USA) and 500 ng of pENTR-CMV_LK8-DS_mE1A_ΔE1B19K was added 16 μL of clonase I reaction buffer (Invitrogen, CA, USA). The reaction mixture was incubated at room temperature for 1 hr with 2 μL of clonase I and then at 37° C. for 10 min with 2 μL of proteinase K (2 μg/μL). 10 μL of the resulting reaction mixture was taken and used to transform E. coli DH5α competent cells which were then spread over ampicillin plates. Plasmid DNA extracted from colony positive in the restriction mapping was identified by DNA sequencing analysis as an adenovirus vector of interest, and then named pAd H5-8DS.

In order to substitute the hexon gene of pAd H5_(—)8DS with SAd19 Hexon, first, 500 ng of pHex-SAd19 Hexon and 50 ng of pAd H5_(—)8DS were linearized respectively with SphI and AsiSI and mixed together before transformation into E. coli BJ5183 by electroporation. Homologous recombination was screened by PCR using a set of the primers of SEQ ID NO: 10 (5′-ATG CGC AAG GTG TAG CCA-3′) and SEQ ID NO: 11 (5′-AGC GTG CTG GCC AGC GTG-3′), which were designed to examine homologous recombination. Starting from denaturation at 94° C. for 5 min, PCR was performed with 30 cycles of denaturation at 94° C. for 30 sec, annealing at 55° C. for 40 sec and extension at 72° C. for 1.5 min, followed by extension at 72° C. for an additional 3 min. The positively screened colonies were subjected to secondary screening by PCR using a set of the primers of SEQ ID NO: 12 (5′-CCC GTT ACA TAA CTT ACG-3′) (CMV sense primer) and SEQ ID NO: 13 (5′-TTA TGG CCT GGG GCG TTT ACA G-3′) (E1A antisense primer), which were designed to amplify a region comprising both LK8 and E1A genes. Starting from denaturation at 94° C. for 5 min, the PCR was performed with 30 cycles of denaturation at 94° C. for 30 sec, annealing at 55° C. for 40 sec and extension at 72° C. for 30 sec, followed by extension at 72° C. for an additional 5 min. DNA was isolated from the clones which were positively screened by the two PCRs and was amplified in E. coli DH5α. A clone which was coincident in all the cutting patterns with EcoRI, SpeI, XbaI and PshAI was secured and named pAd H5/S19_(—)8DS (FIG. 2B). DNA sequencing again identified that pAd H5/S19_(—)8DS contained the hexon of SAd19.

A DNA fragment containing DS promoter was excised from pCR-DS by EcoRI digestion and cloned into the EcoRI site of phRL-null vector (Promega, WI, USA) to generate phRL-DS. A fragment resulting from the treatment of phRL-DS with SalI and PstI was inserted into the SalI and PstI sites of pE1.2 (O.D.260 Inc. Boise, Id. US) shuttle vector, generating pE1.2-DS. The DNA fragment of 1.7 kb size excised from pE1.2-DS by AlwNI digestion was cloned to SfiI site of pAd328 (O.D.260 Inc. Boise, Id. US) by enzyme-ligation method using E. coli XL1-blue electro-competent cells. Plasmid DNA extracted from colony growing on LB plate supplemented with ampicillin and kanamycin was secured by coincidence in all the cutting patterns with EcoRI, SpeI, XbaI and PshAI and named pAd328-DS adenoviral vector (FIG. 2C). The adenovirus E1 gene was amplified from genomic DNA of HAd5 and cloned to pGEM-T easy vector (Promega, WI, USA) to give a recombinant plasmid pGEMT-Ad E1. The pGEMT-Ad E1 was treated very shortly with EcoNI after BssHI digestion to remove a E1B19k region therefrom. E1B19k-deleted pGEMT-Ad E1 was named to pGEMT-Ad E1Δ19k. In order to substitute the E1 gene of pAd328-DS with E1BΔ19k-deleted E1 gene, first, 100 ng of pAd328-DS and 1 μg of SphI-linearized pGEMT-Ad E1Δ19k were mixed together before transformation into E. coli BJ5183 by electroporation. Homologous recombination was screened by digestion with HindIII, SphI and EcoRV. A clone which was coincident in all the cutting patterns was secured and named pAd328-DSΔ19k. According to above procedure described to make pAd H5/S19 8DS plasmid, pAd328 H5/S19_DS and pAd328 H5/S19_DSΔ19k were generated by homologous recombination between pHex-SAd19 Hexon and pAd328_DS or pAd328-DSΔ19k (FIG. 2D).

<2-3> Preparation of Chimeric Adenovirus Recombined with the Hexon of SAd19

The plasmid pAd H5/S19_(—)8DS was linearized with PacI and transfected into A549 cells. 14 Days after the transfection, the cells were observed to undergo cytopathy, and thus collected along with the medium. In order to completely separate the virus therefrom, first, the cells were frozen and thawed three times, followed by centrifugation. The supernatant containing the virus was subjected to two rounds of plaque purification to give pure virus, named Ad H5/S19_(—)8DS virus. Ad H5/S19_(—)8DS virus was identified as chimeric adenovirus having the hexon gene of SAd19 as analyzed by sequencing of their genomic DNA. Ad328 H5/S19_DS and Ad328 H5/S19_DSΔ19k virus were prepared as the above-mentioned procedure for the generation of Ad H5/S19_(—)8DS.

<2-4> Production and Purification of Chimeric Adenovirus Having Hexon of SAd19

A549 lung cancer cells were grown at 80% confluency in 30 culture dishes of 150 mm-size and then infected with Ad H5/S19_(—)8DS virus at MOI of 20. After incubation at 37° C. for two days, the cells were harvested by centrifugation at 12,000×g for 10 min and then suspended in 10 mL of lysis buffer (0.5M Tris, pH8.0, 1 mM MgCl₂). Three rounds of freezing and thawing lysed the cells, followed by refrigerated centrifugation at 12,000×g for 10 min to remove cell debris. In order to prepare a discontinuous CsCl gradient, 8 mL of a CsCl solution having a specific gravity of 1.4 was placed into an ultracentrifuge tube (Beckman, CA, USA) and covered with 6 mL of a CsCl solution having a specific gravity of 1.2 in such a manner as to keep the boundary therebetween definitely. A virus sample filtered through a 0.22 μm filter was loaded onto the CsCl 1.4/1.2 gradient so as not to dishevel the boundary, and the tube was weight balanced with 10 mM Tris-HCl (pH7.9). The tube was applied to a SW28 rotor and ultra-centrifuged at 23,000 rpm for 90 min under a refrigerated condition to form a virus band.

The virus thus separated was again purified using a continuous CsCl gradient ultracentrifugation process. For this, 8 mL of a CsCl solution having a specific gravity of 1.4 was placed in an ultracentrifuge tube (Beckman, CA, USA) and then covered with 6 mL of a CsCl solution having a specific gravity of 1.2 in such a manner as to keep a definite boundary therebetween. Using a gradient station (Biocomp, Canada), a continuous gradient was formed in the tube. The virus sample obtained by the discontinuous CsCl gradient ultracentrifugation was diluted with one volume of 10 mM Tris-HCl (pH7.9) and loaded into the CsCl 1.4/1.2 gradient tube so as not to blur the boundary therebetween. After being weight balanced with 10 mM Tris-HCl (pH7.9), the tube was ultra-centrifuged at 23,000 rpm for 90 min under a refrigerated condition to form a virus band. It was dialyzed three times with PBSG buffer (PBS containing 10% Glycerol), while exchanging the buffer with fresh one every 6 hrs.

Example 3 In Vitro Study of Chimeric Adenovirus Having the Hexon of SAd19

Ad H5/S19_(—)8DS virus was in vitro assayed for selectivity for lung cancer by comparing expression levels of E1A and LK8 in the lung cancer cell line A549 and the normal cell line MRCS both of which were infected at various MOIs with the virus. In addition, Ad H5/S19_(—)8DS virus was measured for affinity for the coagulation factors which mediate blood-circulating virus to liver.

<3-1> MOI-dependent E1A Expression

A549 lung cancer cells and MRCS normal cells, which were both grown at about 80% confluency in 6-well plates, were infected with Ad H5/S19_(—)8DS virus at an MOI of 100, 25, 10 and 1. After incubation at 37° C. for 24 hrs, the cells were harvested by centrifugation at 3,000 rpm for 5 min, suspended in 1×SDS-PAGE buffer (50 mM Tris(pH6.8), 2% SDS, 100 mM dithiothreitol, 0.1% bromophenol blue, 10% Glycerol), heated at 100° C. for 5 min in a water bath, and centrifuged at 10,000 rpm for 2 min. The resulting supernatant was elctrophoresed at 20 mA for about 2 hrs on 4˜12% SDS-PAGE gel (Invitrogen, CA, USA). The protein bands separated on the gel were transferred for about 90 min onto a PVDF membrane using a transfer unit (Invitrogen, CA, USA) in Tris-Glycine buffer (39 mM Glycine, 48 mM Tris, 0.037% SDS, 20% methanol) with an electric field of 300 mA applied thereto. The membrane was blocked at room temperature for one hour with a TBS Blocking solution (Thermo Scientific, IL, USA). A mouse anti-E1A monoclonal antibody (BD Pharmingen, CA, USA), serving as a primary antibody, was 1:3,000 diluted with 5% skim milk/1×TBST buffer, probed at room temperature for one hour and washed for six times each for 5 min with 1×TBST buffer. Anti-mouse HRP (KPL, MA, USA), serving as a secondary antibody, was 1:5,000 diluted with 5% skim milk/1×TBST buffer, probed for 30 min, washed six times each for 5 min with 1×TBST buffer, and reacted with a color developing agent (ECL, Amersham, UK) to visualize an E1A protein band. The expression level of E1A was increased in a MOI-dependent manner, being 100-fold higher in A549 cancer cells than in MRC-5 normal cells (FIG. 3).

<3-2> Affinity for Coagulation Factor X

Ad H5/S19_(—)8DS was analyzed for affinity for coagulation factor X using an SPR (Surface Plasmon Resonance) method. Purified coagulation factor X (HCX-0050, Haematological Technologies Inc., VT, USA) was applied to a CS5 sensor chip (Biacore, Sweden). Each of the purified Ad H5_(—)8DS and Ad H5/S19_(—)8DS viruses was diluted at concentrations of 3.0×10¹¹ VP/mL, 1.5×10¹¹ VP/mL and 0.75×10¹¹ VP/mL in HBSP buffer (10 mM HEPES pH7.4, 150 mM NaCl, 0.005% Tween 20) containing 5 mM CaCl₂. HBSEP (10 mM HEPES pH 7.4, 150 mM NaCl, 3 mM EDTA, 0.005% Tween 20) was used as regeneration buffer for detaching virus from the chip. While the virus solution was passed over the coagulation factor X-immobilized CM5 sensor chip at a flow rate of 30 μL/min, RU values were recorded. At the three different concentrations, the adenovirus serotype 5 Ad H5_(—)8DS showed SPR signals for immobilized factors of 300, 150 and 70RU, respectively, whereas Ad H5/S19_(—)8DS, the chimeric adenovirus having the hexon of SAd19, showed very weak or little affinity for coagulation factor X as the SPR signals were found to be within 5RU at all the three concentrations (FIG. 4A). Ad328 H5/S19_DS and Ad328 H5/S19_DS Δ19k were also assayed for affinity for coagulation factor X by an immunoprecipitation method as described in <3-3> below using coagulation factor X protein instead of factor IX (FIG. 4D).

<3-3> Affinity for Coagulation Factor IX

Ad H5/S19_(—)8DS was assayed for affinity for coagulation factor IX using an immunoprecipitation method. To 1 mL of PBS in a tube was added 1×10¹¹ VP of Ad H5_(—)8DS or Ad H5/S19_(—)8DS, together with 10 μg of purified coagulation factor IX (HCIX-0040, Haematological Technologies Inc., VT, USA), 5 μg of a goat anti-coagulation factor IX antibody and 50 μL of sepharose-protein G (50% slurry), followed by incubation at 4° C. for 2 hrs in an orbital shaker. After centrifugation at 5,000 rpm for 5 min, the sepharose-protein G pellet thus obtained was washed three times with PBS, suspended in 100 μL of 1×SDS-PAGE sample buffer (50 mM Tris(pH6.8), 2% SDS, 100 mM dithiothreitol, 0.1% bromophenol blue, 10% Glycerol), and heated for 5 min. The suspension was centrifuged and the resulting supernatant was electrophoresed at 20 mA for about 2 hrs on 4-12% SDS-PAGE gel. The proteins thus separated were transferred for about 90 min onto a PVDF membrane in a transfer unit containing Tris-Glycine buffer (39 mM Glycine, 48 mM Tris, 0.037% SDS, 20% methanol) to which 300 mA was applied. The membrane was blocked at room temperature for one hour with a TBS Blocking solution (Thermo Scientific, IL, USA). A mouse anti-HAd5 fiber monoclonal antibody (NeoMarkers, CA, USA), serving as a primary antibody, was 1:3,000 diluted with 5% skim milk/1×TBST buffer, probed at room temperature for one hour and washed six times with each for 5 min 1×TBST buffer. Anti-mouse HRP (KPL, MA, USA), serving as a secondary antibody, was 1:5,000 diluted with 5% skim milk/1×TBST buffer, probed for 30 min, washed six times each for 5 min with 1×TBST buffer, and reacted with a color developing agent (ECL, Amersham, UK) to visualize a fiber band. The blots on the PVDF membrane were immersed for one hour in Restore™ Western Blot Stripping Buffer (Thermo Scientific, IL, USA) with shaking in an orbital shaker, washed three times each for 10 min with 1×TBST buffer, and blocked at room temperature for one hour with a TBS Blocking solution. A sheep anti-coagulation factor IX antibody (Affinity Biologicals, Canada), used as a primary antibody, was 1:3,000 diluted with 5% skim milk/1×TBST buffer, probed at room temperature for one hour, and washed six times each for 5 min with 1×TBST buffer. Anti-sheep HRP (KPL, MA, USA), serving as a secondary antibody, was 1:5,000 diluted with 5% skim milk/1×TBST buffer, probed for 30 min, washed for 5 min six times with 1×TBST buffer, and reacted with a color developing agent (ECL, Amersham, UK) to visualize a coagulation factor IX band (FIG. 4B). Ad328 H5/S19_DS and Ad328 H5/S19_DS Δ19k were also assayed for affinity for coagulation factor IX using an immunoprecipitation method as described above (FIG. 4C).

Example 4 In Vivo Study of Chimeric Adenovirus Having the Hexon of SAd19 <4-1> Biodistribution

Ad H5/S19_(—)8DS was intravenously injected in a dose of 3×10¹⁰ VP into Balb/c normal mice and nude mice, both 6 weeks old. Two days after injection, DNA was isolated from the brain, the liver, the lung, the heart, the thymus, the spleen, the ovary, the uterus and blood using a DNeasy Blood and Tissue Kit (QIAGEN, Germany). The isolated DNA was quantitatively analyzed using an OD spectrophotometer and used in an amount of 200 ng as a template for PCR. The E4 region of adenovirus was amplified by PCR using a set of primers of SEQ ID NO: 14 (5′-ACT CGA GCA CGT TGT GCA TTG TCA-3′) and SEQ ID NO: 15 (5′-TGT CGA CTA GTT TTC TTA AAA TGG-3′). Starting from denaturation at 94° C. for 5 min, PCR was performed with 30 cycles of denaturation at 94° C. for 30 sec, annealing at 55° C. for 40 sec and extension at 72° C. for 1 min, followed by extension at 72° C. for additional 3 min. The PCR products were run on 1% agarose gel in the presence of an electric field to analyze the distributions of adenovirus by organs. When injected, the HAd5, i.e., Ad H5_(—)8DS, was most highly observed in the liver and the lung, and partially detected in the heart and the spleen. In contrast, the chimeric adenovirus having the hexon of SAd19, Ad H5/S19_(—)8DS virus, was mostly detected in the heart and the spleen, and only a part was detected in the liver and the lung (FIG. 5). This distribution pattern is quite different from the biodistribution of adenovirus serotype 5, which is known to be transduced into the liver upon intravenous injection and induce hepatotoxicity upon injection in large doses. That is, Ad H5/S19_(—)8DS virus was transduced in a very small amount into the liver, as inferred from the observation of Example <3-2> that the virus showed little affinity for coagulation factor X.

Example 5 In Vitro Assay for Ability of Chimeric Adenovirus Having the Hexon of SAd19 to Evade Immune Recognition of HAd5 Neutralizing Antibody <5-1> Examination of the Effect of Anti-HAd5-Positive Plasma on Transduction of Ad H5/S19_(—)8DS and Ad328 H5/S19_DS by E1A Expression Pattern

Wild-type HAd5 was intramuscularly injected at a dose of 1×10¹¹ VP into the hind legs of mice and two weeks thereafter, the same dose of the virus was injected again to boost an immune response. Sera were separated from the blood taken from all of the virus-injected mice and then measured for anti-adenovirus antibody levels. In this regard, 1/25, 1/100, and 1/1,000 dilutions of the sera were added to adenovirus-coated ELISA plates, incubated for one hour, and washed three times with PBST (PBS containing 0.1% Tween20), followed by incubation for one hour with a 1/5,000 dilution of an HRP-conjugated anti-mouse IgG antibody. After the plates were washed five times with PBST (PBS containing 0.1% Tween20), a color was developed by reaction for 30 min with a TMB substrate and termination with 1 M phosphoric acid. The plates were measured for absorbance. They were regarded as inducing a positive immune response when the absorbance thereof was 50% or higher as compared with that of a positive control, prepared by reacting with a 1/1000 dilution of an anti-adenovirus antibody (AbD Serotec, NC, USA). A549 cells, grown at 90% confluency in 6-well plates, were infected at MOI of 25 with Ad H5/S19_(—)8DS or Ad328 H5/S19_DS one hr before being incubated at room temperature with the mouse plasma which were determined to be of positive immune response. After incubation at 37° C. for 24 hrs, the cells were harvested by centrifugation at 3,000 rpm for 5 min, suspended in 1×SDS-PAGE sample buffer (50 mM Tris (pH6.8), 2% SDS, 100 mM dithiothreitol, 0.1% bromophenol blue, 10% glycerol), heated at 100° C. for 5 min in a water bath, and centrifuged at 10,000 rpm for 2 min. The clarified supernatant was run for about 2 hrs on 4-12% SDS-PAGE gel in the presence of 20 mA using an electrophoresis kit (Novex). The separated proteins were transferred for 90 min onto a PVDF membrane in a transfer unit (Novex) containing Tris-Glycine buffer (39 mM Glycine, 48 mM Tris, 0.037% SDS, 20% methanol) with an electric field of 300 mA applied thereinto. The membrane was blocked at room temperature for one hour with a TBS Blocking solution (Thermo Scientific, IL, USA). The membrane was incubated at room temperature for one hour with a 1:3,000 dilution of mouse anti-E1A monoclonal antibody (BD Pharmingen, CA, USA), a primary antibody, in 5% skim milk/1×TBST buffer and then washed six times each for 5 min with 1×TBST buffer. Incubation with a 1:5,000 dilution of anti-mouse HRP (KPL, MA, USA) as a secondary antibody in 5% skim milk/1×TBST buffer for 30 min was followed by washing six times each for 5 min with 1×TBST buffer. An E1A protein band was visualized with a color developing reagent (ECL, Amersham, UK). Whereas the transduction of Ad H5_(—)8DS was inhibited by the anti-HAd5 antibody-positive plasma, there were no effects of the anti-HAd5 antibody-positive plasma on the transduction of the chimeric adenovirus Ad H5/S19_(—)8DS (FIG. 6A), Ad328 H5/S19_DS and Ad328 H5/S19_DS Δ19k (FIG. 6B).

<5-2> Examination of the Effect of Anti-HAd5-Positive Plasma on H5/S19_(—)8DS Transduction by Immunostaining

After being incubated at room temperature for one hour with the mouse plasmas which were determined to be of positive immune response, 90% confluently cultured A549 cells were infected with Ad H5/S19_(—)8DS or Ad H5/S19_DS at an MOI of 25, followed by incubation at 37° C. for two days. The cells were fixed with cold methanol and blocked for one hour with a protein-free T20 (TBS) blocking buffer (Thermo Scientific, IL, USA). The cells were incubated for one hour with a dilution (1/3,000) of a mouse anti-E1A monoclonal antibody (BD Pharmingen, CA, USA) in PBST buffer and washed six times each for 5 min with PBST buffer. Then, the cells were again treated for one hour with a dilution (1/5,000) of a HRP-conjugated anti-mouse secondary antibody in PBST buffer, washed six times each for 5 min with PBST buffer, and reacted with a DAB solution to produce a color. The anti-HAd5 antibody-positive plasma was found to inhibit the transduction of Ad H5_(—)8DS, but to have no influence on the transduction of the chimeric adenovirus Ad H5/S19_(—)8DS (FIG. 7A), Ad328 H5/S19_DS and Ad H5/S19_DSΔ19k (FIG. 7B).

<5-3> In Vivo Examination into Ability of Chimeric Adenovirus Having the Hexon of SAd19 to Evade Immune Recognition of HAd5 Neutralizing Antibody

Wild-type HAd5 was intramuscularly injected at a dose of 1×10¹¹ VP into the hind legs of hamster and, two weeks thereafter, which the same dose of the virus was injected again to induce an immune response. Sera were separated from the blood taken from all of the virus-injected hamsters and then measured for anti-adenovirus antibody level therein. In this regard, 1/25, 1/100, and 1/1,000 dilutions of the sera were added to adenovirus-coated ELISA plates, incubated for one hour, and washed three times with PBST (PBS containing 0.1% Tween20), followed by incubation for one hour with a 1/5,000 dilution of an HRP-conjugated anti-hamster IgG antibody. After the plates were washed five times with PBST (PBS containing 0.1% Tween20), a color was developed by reaction for 30 min with a TMB substrate and termination with 1 M phosphoric acid. The plates were measured for absorbance. They were regarded as inducing a positive immune response when the absorbance thereof was 50% or higher as compared with that of a positive control, prepared by reacting with a 1/1,000 dilution of an anti-adenovirus antibody. The immunized hamsters into which HAd5, i.e., Ad H5_(—)8DS was intravenously injected at a dose of 1×10¹¹ VP was found to be too low in blood LK8 level to detect. In contrast, the intravenous injection of Ad H5/S19_(—)8DS at a dose of 1×10¹¹ VP ensured a blood LK8 level of 200 ng/mL or higher, and the expression amount was maintained at a level of 200 ng/mL or higher for 28 days, indicating that the chimeric adenovirus having the hexon of SAd19 is not inhibited on their transduction by the anti-human adenovirus serotype 5 neutralizing antibody (FIG. 8).

Example 6 Toxicity of Chimeric Adenovirus Having the Hexon of SAd19

The hexon of SAd19 was studied for toxicity. To this end, the virus was intravenously injected at doses of 1×10¹¹ VP, 5×10¹⁰ VP, 1×10¹⁰ VP, 5×10⁹ VP, and 1×10⁹ VP, respectively, into five groups of five Balb/c mice which were weighed every other day. At week three and six after the injection, bloods and sera were taken from the mice and analyzed for leukocyte, erythrocyte, platelet and hemoglobin levels, hematocrit, MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Hemoglobin Concentration), MCHC (Mean Corpuscular Hemoglobin Concentration) and differential leucocyte count. An examination was made of levels of albumin, total protein, SGPT (ALT), SGOT (AST) and ALP for liver function tests, creatinine and BUN for kidney function tests, creatinine kinase for muscle tests, and total cholesterol and glucose for metabolism tests. Of 5 mice in the group which was injected at a dose of 1×10¹¹ VP with the human adenovirus serotype 5 virus Ad H5_(—)8DS, four were dead on day 5 while the remaining one was heavily sick. They were found to suffer from hepatocirrhosis by an autopsy, with no abnormality in the other organs. All the other groups were observed to be normal, as examined by autopsy (FIG. 9).

<6-1> Blood Test

The HAd5, i.e., Ad H5_(—)8DS was intravenously injected at doses of 1×10¹¹ VP, 5×10¹⁰ VP, 1×10¹⁰ VP, 5×10⁹ VP, and 1×10⁹ VP. On day 5, all of the mice injected with 1×10¹¹ VP of the virus were dead. On the other hand, the other groups showed no observations of abnormal toxicity. There were no statistical differences in hematological and blood biochemistry tests between the test groups and the negative control group injected with PBS (FIG. 10). Abnormal toxicity observations were found in none of the groups to which the chimeric adenovirus having the hexon of SAd19, Ad H5/S19_(—)8DS, was injected at doses of 1×10¹¹ VP, 5×10¹⁰ VP, 1×10¹⁰ VP, 5×10⁹ VP and 1×10⁹ VP. Also, no statistical differences in hematological and blood biochemistry tests were found between the test groups and the PBS-injected negative control group (FIG. 11). Hepatotoxicity detected in the group injected with a maximum dose of HAd5 was not observed in the corresponding group injected with the chimeric adenovirus having the hexon of SAd19.

<6-2> Biopsy

The brain, the heart, the liver, the lung, the kidney, the spleen, the uterus and the ovary were excised from the injected mice, fixed with 3.7% neutral formalin, embedded in paraffin, sliced, and stained with H&E. No abnormalities of organs were found in all of the test groups except the group injected with 1×10¹¹ VP of human adenovirus serotype. Liver biopsy results showed massive hepatic necrosis in the 1×10¹¹ VP-injected group, which was thought to induce acute hepatic failure of which the mice died. This was a general observation of adenoviral hepatotoxicity. As for the chimeric adenovirus having the hexon of SAd19, it did not hepatotoxicity even when injected at a dose of 1×10¹¹ VP, indicating that the hexon of SAd19 may be a promising solution to the hepatotoxicity problem caused when HAd5 is used.

Example 7 Anti-Tumor Activity of Chimeric Adenovirus Having the Hexon of SAd19 in Animal Tumor Model <7-1> Tumor-Selective, Anti-Tumor Activity of Chimeric Adenovirus on Human Lung Cancer Xenograft Animal Model

The non-small cell lung cancer (NSCLC) cell line NCI-H460 was subcutaneously injected at a dose of 5×10⁶ cells into the right flank of immune-deficient Balb/c nude mice to form tumors 50˜100 mm³ in size. The mice were randomly divided into four groups of five mice. Mice of control groups were intravenously administered with either replication defective adenovirus carrying LK8 gene, Ad-LK8, at a dose of 1×10⁹ pfu or PBS, three times at regular intervals of two days. As for test groups, they were intravenously injected with Ad H5/S19_(—)8DS in doses of 1×10⁹ pfu and 2×10⁸ pfu, three times at regular intervals. The tumors were measured for size every two or three days to plot tumor growth curves. On Day 24 after the first injection of virus, the group injected at a dose of 1×10⁹ pfu with Ad H5/S19_(—)8DS exhibited a 74% higher tumor growth inhibition rate than the PBS-administered group and a 64% higher rate than the Ad-LK8-administered group. On the other hand, the group injected at a dose of 2×10⁸ pfu with Ad H5/S19_(—)8DS showed a 61% higher tumor growth inhibition rate than the PBS-administered group, and a 48% higher rate than the Ad-LK8-administered group. A 2-way RM ANOVA test revealed statistical significances of both the groups injected with Ad H5/S19_(—)8DS over the PBS-administered group from 17 days after the injection (Day 17 after the injection, P<0.05; Days 21 and 24 after the injection, P<0.01) (FIG. 12).

<7-2> Tumor-Selective, Anti-Tumor Activity of Chimeric Adenovirus on Human Lung Cancer Orthotopic Animal Model Immunized with HAd5

Balb/c nude mice were immunized with HAd5 by two rounds of intramuscular injection at a dose of 1×10¹⁰ VP for each round at regular intervals of two weeks into the hind leg thereof. Blood taken from the mice was found to contain anti-HAd5 antibody. The NSCLC cell line NCI-H2172 was inoculated at a dose of 1×10⁶ cells into the tail vein. The naëve and immunized mice were received triple intravenous injections of either Ad-LK8, Ad H5/S19_(—)8DS or Ad H5_(—)8DS on day 7, 9 and 11 after tumor inculation at an injection dose of 1×10⁹ pfu. At Week 6, the lung was excised from the mice (FIG. 13). The tumors generated in the lung were counted and divided into groups by size: x≦0.5 cm, 0.5 cm≦x≦0.7 cm, and 0.7 cm<x≦1 cm, which were respectively given 5, 7 and 10 points. The tumor generated in the lung was found to count, on average, 18.6 in the PBS-administered, negative control group, and 11.2 in the Ad-LK8-administered group. As for the groups administered with Ad H5/S19_(—)8DS, they were found to have 5.6 and 5.4 tumors, on average, in the lung when immunized or not immunized with the HAd5, respectively. On the other hand, mice in the groups administered with Ad H5_(—)8DS were found to have 10.8 and 6.2 tumors, on average, in the lungs of immunized or naïve mice. Therefore, Ad H5/S19_(—)8DS showed almost the same titers irrespective of immunization, but Ad H5_(—)8DS showed efficacy decreased significantly by anti-HAd5 antibody. Mean lung volumes were measured to be 274 mm³ in normal mice, 570 mm³ in the PBS-administered group, and 480 mm³ in the Ad-LK8-administered group. However, the mouse groups injected with Ad H5/S19_(—)8DS were found to have 370 mm³ lungs and 360 mm³ lungs, respectively, when immunized or non-immunized. There was no significant difference in lung volume between them. In the groups administered with Ad H5_(—)8DS, mean lung volumes were 410 mm³ and 350 mm³, respectively, when immunized or non-immunized. Mean weights of the lungs were measured to be 170 mg in the normal mice, 376 mg in the PBS-administered group and 278 mg in the Ad-LK8-administered group. When injected with Ad H5/S19_(—)8DS, mean lung weight of both the immunized or non-immunized mouse groups was measured to be 218 mg, while mean lung weights of Ad H5_(—)8DS-administered groups were 240 mg for immunized and 230 mg for non-immunized. Turning to the scores gained according to tumor sizes, they were measured to be, on average, 107.8 in the PBS-administered group and 60.8 in the Ad-LK8-administered group. When injected with Ad H5/S19_(—)8DS, the immunized group and the non-immunized group gained 28 and 27 points, respectively. On the other hand, the immunized group and non-immunized group gained 57.2 and 32.6, respectively, when injected with Ad H5_(—)8DS (FIG. 14). Taken together, these data indicate that Ad H5/S19_(—)8DS, irrespective of immunization with HAd5, can exert anti-tumor activity even when intravenously injected.

While the invention has been described with respect to the above specific embodiments, it should be recognized that various modifications and changes may be made to the invention by those skilled in the art which also fall within the scope of the invention as defined by the appended claims. 

1. A hexon isolated from simian adenovirus serotype 19 having the amino acid sequence of SEQ ID NO:
 16. 2. A DNA encoding the hexon of claim
 1. 3. The DNA of claim 2 having the nucleotide sequence of SEQ ID NO:
 3. 4. A hypervariable region (HVR) having the amino acid sequence of SEQ ID NO: 21 isolated from simian adenovirus serotype
 19. 5. A DNA encoding the HVR of claim
 4. 6. The DNA of claim 5 having the nucleotide sequence of SEQ ID NO:
 20. 7. A chimeric adenovirus having a normative amino acid sequence in the hexon by the substitution of the hexon protein having the amino acid sequence of SEQ ID NO: 16, or seven (7) or more consecutive residues therefrom.
 8. The chimeric adenovirus of claim 7, wherein the normative amino acid sequence is the HVR having the amino acid sequence of SEQ ID NO:
 21. 9. The chimeric adenovirus of claim 7, wherein the normative amino acid sequence is a fragment of the HVR selected from the group consisting of: amino acid residues 11 to 41 of SEQ ID NO: 21; amino acid residues 46 to 52 of SEQ ID NO: 21; amino acid residues 69 to 78 of SEQ ID NO: 21; amino acid residues 106 to 119 of SEQ ID NO: 21; amino acid residues 126 to 138 of SEQ ID NO: 21; amino acid residues 160 to 173 of SEQ ID NO: 21; and amino acid residues 275 to 303 of SEQ ID NO:
 21. 10. The chimeric adenovirus of claim 7, which is a human adenovirus.
 11. The chimeric adenovirus of claim 10, wherein the human adenovirus is selected from the group consisting of human adenovirus serotypes 2, 3, 5, 11, 24, 26, 30, 34, 35, 36, 41, 48, 49, and
 50. 12. The chimeric adenovirus of claim 7, wherein the chimeric adenovirus further comprises a therapeutic transgene.
 13. The chimeric adenovirus of claim 12, wherein the therapeutic transgene is selected from the group consisting of tumor suppressor gene, antigenic gene, cytotoxic gene, cytostatic gene, suicide gene, anti-angiogenic gene, and immune-modulatory gene.
 14. The chimeric adenovirus of claim 13, wherein the tumor suppressor gene is selected from the group consisting of p53 gene, APC gene, DPC-4/Smad-4 gene, BRCA-1 gene, BRCA-2 gene, WT-1 gene, retinoblastoma gene, MMAC-1 gene, adenomatous polyposis coil protein, DCC (deleted in colorectal cancer) gene, MMSC-2 gene, NF-1 gene, NF-2 gene, MTS1 gene, CDK4 gene, and VHL gene; the antigenic gene is carcinoembryonic antigen (CEA), CD3, CD133, CD44, or p53; the cytotoxic gene is selected from the group consisting of genes coding Pseudomonas exotoxin, ricin toxin, and diphtheria toxin; the cytostatic gene is selected from the group consisting of p21, retinoblastoma gene, E2F-Rb fusion protein gene, a gene coding cyclin-dependent kinase inhibitor, and growth arrest specific homeobox (GAX) gene; the suicide gene is selected from the group consisting of genes coding herpes simplex virus thymidine kinase, varicella thymidine kinase, cytosine deaminase, purine nucleoside phosphorylase, beta-lactanase, carboxypeptidase G2, cytochrome P450-2B1, nitroreductase, beta-glucuronidase and TRAIL (TNF related apoptosis-inducing ligand); the anti-angiogenic gene is selected from the group consisting of genes coding vascular endothelial growth factor (VEGF), soluble VEGF receptor, angiostatin, endostatin, and apolipoprotein (a) kringle domain (LK8); and the immune-modulatory gene is selected from the group consisting of genes coding CD16, CTLA-4, IL24 and GM-CSF.
 15. A composition comprising the chimeric adenovirus of claim
 7. 16. A method for delivering a therapeutic transgene to a mammalian cell comprising introducing into said cell the chimeric adenovirus of claim
 12. 17. A method for treating cancers comprising administering into a subject the chimeric adenovirus of claim
 12. 18. A method for preparing an adenoviral vector for gene therapy comprising substituting seven (7) or more amino acid residues in the hexon of a human adenovirus with seven (7) or more residues of the hexon protein having the amino acid sequence of SEQ ID NO:
 16. 19. An isolated host cell comprising the chimeric adenovirus of claim
 7. 20. The isolated host cell of claim 19, wherein the isolated host cell is a human cell. 